[[: bullseye/sid: division by 0 (error token is "sid")

[speed47]

I'm getting this output on a container without OpenSSH installed:

hardening                 [INFO] Treating /opt/cis-hardening/bin/hardening/5.2.15_ssh_cry_kex.sh
5.2.15_ssh_cry_kex        [INFO] Working on 5.2.15_ssh_cry_kex
5.2.15_ssh_cry_kex        [INFO] [DESCRIPTION] Checking key exchange ciphers.
/opt/cis-hardening/bin/hardening/5.2.15_ssh_cry_kex.sh: line 79: [[: bullseye/sid: division by 0 (error token is "sid")
/opt/cis-hardening/bin/hardening/5.2.15_ssh_cry_kex.sh: line 81: [[: bullseye/sid: division by 0 (error token is "sid")
/opt/cis-hardening/bin/hardening/5.2.15_ssh_cry_kex.sh: line 81: [[: bullseye/sid: division by 0 (error token is "sid")
5.2.15_ssh_cry_kex        [INFO] Checking Configuration
5.2.15_ssh_cry_kex        [INFO] Performing audit
5.2.15_ssh_cry_kex        [ KO ] openssh-server is not installed!
5.2.15_ssh_cry_kex        [ KO ] Check Failed

Maybe a check of the existence of the file is missing or something?